.338 Norma Magnum

[X-RingCustomGunsmithing]

Just curious why everyone is so paranoid about building the .338 Norma magnum on a 700 long action. They already make after market bolts with the Lapua bolt face for it. The designer of the Norma designed this cartridge for a 700 platform and to fit in a normal size mag box. I really dont see the issue open up a bolt face laterally to .585 the lugs are still lugs your not loosing any metal on the lugs at all due to the nose on the Remington bolt. I keep reading about pressures of the case being brought up a lot but Remington chambers the 700 long action to fire the .300 Ultra mag as it is with an operation pressure of 65,000 PSI and the max pressure of the 338 Norma is around 62,000 PSI so it is under what a standard caliber already chambered and fit for that action. So I don't know why its recommended against building on this type of action. I am planning on starting mine come January and was wondering just what I am missing or are people that afraid to try something.

 

[Robert]

Just curious why everyone is so paranoid about building the .338 Norma magnum on a 700 long action. They already make after market bolts with the Lapua bolt face for it. The designer of the Norma designed this cartridge for a 700 platform and to fit in a normal size mag box. I really dont see the issue open up a bolt face laterally to .585 the lugs are still lugs your not loosing any metal on the lugs at all due to the nose on the Remington bolt. I keep reading about pressures of the case being brought up a lot but Remington chambers the 700 long action to fire the .300 Ultra mag as it is with an operation pressure of 65,000 PSI and the max pressure of the 338 Norma is around 62,000 PSI so it is under what a standard caliber already chambered and fit for that action. So I don't know why its recommended against building on this type of action. I am planning on starting mine come January and was wondering just what I am missing or are people that afraid to try something.

On technical temrs (you are a gunsmith), the pressure per square inch or centimetre is not the paeameter.

What is to consider is the backthrust, wich is proprotionnal with the rear case surface and max. allowed pressure.

On my CIP listing, .338 Norma is about 18% more surface, while CuP or Piezo max. pressures are quite similar...

R.G.C

 

[Rem06]

i had a 300 Norma built on a rem 700 action and have 100rds through it just fine.

 

[Larryh128]

I wouldn't be too concerned, there were THOUSANDS of them built on surplus 98 actions. An old gunsmith friend of mine probably made 100 himself. I can also know that he never loaded them down, always wound to the top.

 

[shortgrass]

I'm probably not telling anyone anything new, but, the .338 Norma Mag is based off of the .416 Rigby case. Where as, the .308 Norma mag has the same head size as the .300 Win Mag. The bigger bolt face of the Rigby case exerts more bolt thrust as Robert mentioned. And, after opening up a Rem 700 bolt face, there's not much left. Would be better sized on an action that uses a 3/4" diameter bolt.

 

[TRECustom]

I would use a Wby MK V action with a .378 cal bolt face, or a std mag bolt face and open it for the .338 Norma. I wouldn't use the Remington for anything bigger than a .540 bolt face.

The Mk V will also give you about .100" longer mag well than the Remington.

Just my opinion, Tom

 

[X-RingCustomGunsmithing]

The PTG replacement bolts for the long action with the 416 bolt face that go right in the action are regular size arent they. Looks like a replacement bolt but not looking to spend 250 when I can open the one in it already to get the same thing and put the sako extractor in.

 

[X-RingCustomGunsmithing]

Well I just got back from shot show and go to talk with savage about their 338 lapua actions. I asked what they did to build their action and bolt they said its the same as the regular magnums they did only change one thing they added .050 thousandths to the receiver lug surfaces cause they had the chance to but the bolt is a plain magnum opened up nothing different at all in that respect so the bolt thrust wouldn't shear any lugs with the lapua or norma mag the lugs are not thicker wider or any different metal.

 

[Robert]

The PTG replacement bolts for the long action with the 416 bolt face that go right in the action are regular size arent they. Looks like a replacement bolt but not looking to spend 250 when I can open the one in it already to get the same thing and put the sako extractor in.

I have neverseen a Rem 700 bolt modified to accept a self-gripping extactor (call it Sako f you prefer), but I do presume its pocket is milled into the right lug of the Bolt? Correct me if I am wrong.

This would take away at least 50% of the right lug shear area, notwithstanding the uneven bearing caused by unavoidable flexion of the section-reduced right lug.
This modification may be possible with a .308 bolt face, but, larger could only led for problems IMHO.

I have just measured a Rem 700 bolt head (17,6mm). If it was opened uo for .338 Norma or Lapua (15mm), it would remain to enclose the case head a thin ring of metal 1,3mm (.051) wide. Not very much to contain a possible blowback...most certainly transforming the said tiny ring in grenade splits!!!.
R.G.C

 

[TRECustom]

Robert, the slot for the Sako or M-16 extractor is milled at the root of the right hand lug on the upper side. It does undercut some of the bolt at the base of the lug. In battery, the right hand lug rotates to 6 o'clock and the extractor is at about 5 o'clock. When the bolt is opened, this places the extractor at about 2 o'clock, instead of at 3 o'clock like the factory extractor. Some have reported ejection problems when a fired case hits the scope barrel or windage knob, but I haven't had it happen to me.

Back to your question; it looks like it weakens the area of the bolt under the locking lug, but I don't know if it's significant. It's a common alteration to Remington bolts, and I haven't heard of any failures. I still recommend the Wby MK V action.

Tom

 

[Robert]

Robert, the slot for the Sako or M-16 extractor is milled at the root of the right hand lug on the upper side. It does undercut some of the bolt at the base of the lug. In battery, the right hand lug rotates to 6 o'clock and the extractor is at about 5 o'clock. When the bolt is opened, this places the extractor at about 2 o'clock, instead of at 3 o'clock like the factory extractor. Some have reported ejection problems when a fired case hits the scope barrel or windage knob, but I haven't had it happen to me.

Back to your question; it looks like it weakens the area of the bolt under the locking lug, but I don't know if it's significant. It's a common alteration to Remington bolts, and I haven't heard of any failures. I still recommend the Wby MK V action.

Tom

Tom,
Thanks for the clarification . This 2 O”clock position bolt open is quite logical. I will have to search on the net for a picture of a bolt head such modified.
However, it remains then that the extractor cannot protrude out of the bolt diameter, even when it override the case rim and this limit significantly the maximum possible f iameter of the case head. With a 17,6mm bolt diameter and for instance a 12mm (.473’) case head, take 1mm for allowing the extractor to override the rim, then, the extractor cannot be thickher than 1,8mm (.070’).. Not very much indeed…. But maybe I am wrong again?
I agreement with you, I think for a .587’ casehead dioameter, a bolt with protruding lugs should not be smaller diameter than .750’, . 875’ being even better. Integral lugs bol (lugs and bolt body same diameter) no less than 24mm- .945’.
R.G.C

 

[okedoke]

Finally, someone understands the differences between .338 norma mag. & the 338 lapua mag. #### the 700 rem will handle the pressure of either cartridge, the real ? is the col- or cartridge overall length. While the lapua is pushing the limits of the rem. 700 action, it is no problem to build the 338 norma mag., & openning the bolt face & installing a sako extractor is not a problem but it is easier to just call pacific tool & guage & tell dave to send you a proper bolt that will be pictured in the on-line catalog. PS. accuracy international, remington, savage, sako, & armalite corp. still offer 338 lm & will at yor request, build a 338 nm.----------take care craig

 

[shortgrass]

Robert, the slot for the Sako or M-16 extractor is milled at the root of the right hand lug on the upper side. It does undercut some of the bolt at the base of the lug. In battery, the right hand lug rotates to 6 o'clock and the extractor is at about 5 o'clock. When the bolt is opened, this places the extractor at about 2 o'clock, instead of at 3 o'clock like the factory extractor. Some have reported ejection problems when a fired case hits the scope barrel or windage knob, but I haven't had it happen to me.

Back to your question; it looks like it weakens the area of the bolt under the locking lug, but I don't know if it's significant. It's a common alteration to Remington bolts, and I haven't heard of any failures. I still recommend the Wby MK V action.

Tom

Tom,
Thanks for the clarification . This 2 O”clock position bolt open is quite logical. I will have to search on the net for a picture of a bolt head such modified.
However, it remains then that the extractor cannot protrude out of the bolt diameter, even when it override the case rim and this limit significantly the maximum possible f iameter of the case head. With a 17,6mm bolt diameter and for instance a 12mm (.473’) case head, take 1mm for allowing the extractor to override the rim, then, the extractor cannot be thickher than 1,8mm (.070’).. Not very much indeed…. But maybe I am wrong again?
I agreement with you, I think for a .587’ casehead dioameter, a bolt with protruding lugs should not be smaller diameter than .750’, . 875’ being even better. Integral lugs bol (lugs and bolt body same diameter) no less than 24mm- .945’.
R.G.C

Badger recommends opening the counterbore in the end of the barrel to .785", so there's room for the extractor to snap over the rim, when using their m-16 style extractor. So much for "The 3 Rings of Steel"!